When image content such as video is sent through a communication system, the image content is typically digitized into sample values, which are compressed before transmission and decompressed after receipt. Various factors affect how the sample values are interpreted, displayed, and perceived.
A convention defined in a standard, proprietary format or industry practice, or other implicit understanding, may indicate how sample values should be interpreted or displayed when they are received. Alternatively, metadata may be explicitly signaled that indicates how sample values should be interpreted or displayed. In particular, encoded data for an image or video can include information that identifies (by enumeration or other means) how sample values should be interpreted or displayed. For example, the metadata can be parameters such as color primary chromaticity values, transfer characteristics (informally known as gamma), and matrix coefficients. Such metadata typically relates to the characteristics of source (original) sample values or characteristics of a reference, or “master,” display device used when editing sample values during a production process, so as to optimize presentation on display devices like the reference display device. Display of image content, however, depends on more than the characteristics of source content and characteristics of a display device.